/usr/share/pyshared/pysnmp/proto/secmod/rfc3414/auth/hmacmd5.py is in python-pysnmp4 4.2.5-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 | try:
from hashlib import md5
except ImportError:
import md5
md5 = md5.new
from pyasn1.type import univ
from pysnmp.proto.secmod.rfc3414.auth import base
from pysnmp.proto.secmod.rfc3414 import localkey
from pysnmp.proto import errind, error
_twelveZeros = univ.OctetString((0,)*12).asOctets()
_fortyEightZeros = (0,)*48
# rfc3414: 6.2.4
class HmacMd5(base.AbstractAuthenticationService):
serviceID = (1, 3, 6, 1, 6, 3, 10, 1, 1, 2) # usmHMACMD5AuthProtocol
__ipad = [0x36]*64
__opad = [0x5C]*64
def hashPassphrase(self, authKey):
return localkey.hashPassphraseMD5(authKey)
def localizeKey(self, authKey, snmpEngineID):
return localkey.localizeKeyMD5(authKey, snmpEngineID)
# 6.3.1
def authenticateOutgoingMsg(self, authKey, wholeMsg):
# Here we expect calling secmod to indicate where the digest
# should be in the substrate. Also, it pre-sets digest placeholder
# so we hash wholeMsg out of the box.
# Yes, that's ugly but that's rfc...
l = wholeMsg.find(_twelveZeros)
if l == -1:
raise error.ProtocolError('Cant locate digest placeholder')
wholeHead = wholeMsg[:l]
wholeTail = wholeMsg[l+12:]
# 6.3.1.1
# 6.3.1.2a
extendedAuthKey = authKey.asNumbers() + _fortyEightZeros
# 6.3.1.2b --> noop
# 6.3.1.2c
k1 = univ.OctetString(
map(lambda x,y: x^y, extendedAuthKey, self.__ipad)
)
# 6.3.1.2d --> noop
# 6.3.1.2e
k2 = univ.OctetString(
map(lambda x,y: x^y, extendedAuthKey, self.__opad)
)
# 6.3.1.3
d1 = md5(k1.asOctets()+wholeMsg).digest()
# 6.3.1.4
d2 = md5(k2.asOctets()+d1).digest()
mac = d2[:12]
# 6.3.1.5 & 6
return wholeHead + mac + wholeTail
# 6.3.2
def authenticateIncomingMsg(self, authKey, authParameters, wholeMsg):
# 6.3.2.1 & 2
if len(authParameters) != 12:
raise error.StatusInformation(
errorIndication=errind.authenticationError
)
# 6.3.2.3
l = wholeMsg.find(authParameters.asOctets())
if l == -1:
raise error.ProtocolError('Cant locate digest in wholeMsg')
wholeHead = wholeMsg[:l]
wholeTail = wholeMsg[l+12:]
authenticatedWholeMsg = wholeHead + _twelveZeros + wholeTail
# 6.3.2.4a
extendedAuthKey = authKey.asNumbers() + _fortyEightZeros
# 6.3.2.4b --> noop
# 6.3.2.4c
k1 = univ.OctetString(
map(lambda x,y: x^y, extendedAuthKey, self.__ipad)
)
# 6.3.2.4d --> noop
# 6.3.2.4e
k2 = univ.OctetString(
map(lambda x,y: x^y, extendedAuthKey, self.__opad)
)
# 6.3.2.5a
d1 = md5(k1.asOctets()+authenticatedWholeMsg).digest()
# 6.3.2.5b
d2 = md5(k2.asOctets()+d1).digest()
# 6.3.2.5c
mac = d2[:12]
# 6.3.2.6
if mac != authParameters:
raise error.StatusInformation(
errorIndication=errind.authenticationFailure
)
return authenticatedWholeMsg
|